use robolectric for android tests

owncloudComLibrary/build.gradle

@@ -15,6 +15,7 @@ dependencies {
     kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshiVersion"
 
     testImplementation 'junit:junit:4.13.2'
+    testImplementation 'org.robolectric:robolectric:4.3.1'
 }
 
 android {
@@ -37,4 +38,10 @@ android {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
+
+    testOptions {
+        unitTests {
+            includeAndroidResources = true
+        }
+    }
 }